Hydrothermal Preparation And Photocatalytic Performance Of Different Elements Doping ZnO Films

Semiconductor photocatalysis technology has the ability to remove organic pollutants in water,and is considered an effective way to solve water pollution.At present,metal oxides such as TiO2,SnO2 and ZnO are widely used as photocatalysts.Among them,ZnO is an attractive semiconductor photocatalyst with wide band gap(3.37 eV),and its high exciton binding energy(60 meV)leads to efficient exciton emission at room temperature.In addition,as a photocatalyst,ZnO has many advantages such as low cost,non-toxicity,and more absorption of light quantum However,due to the rapid recombination of photogenerated carriers,the photocatalytic efficiency of ZnO is suppressed.Therefore,the recombination of electron-hole pairs must be suppressed to improve photocatalytic performance.The method of doped different elements into the ZnO photocatalyst has attracted widespread attentionIn order to overcome the problems of easy dispersion and recycling of traditional powder photocatalysts.Polyethylene terephthalate(PET)has a high transmittance in the visible range,which can be used as the substrate material.Graphene or indium tin oxide(ITO)-coated PET(GPET or PET-ITO)combines the excellent properties of PET and graphene/ITO to provide a more excellent flexible growth substrate for the growth of ZnOIn this paper,doped ZnO/GPET or ZnO/PET-ITO composites were synthesized by a simple,green hydrothermal method by using GPET or PET-ITO as the growth substrate.The prepared samples were fundamentally characterized by X-ray Diffraction(XRD),Field Emission Scanning Electron Microscope(FE-SEM),X-ray Photoelectron Spectroscopy(XPS),etc.,and the growth mechanism of the ZnO nanosheet structure was explored.The photocatalytic performance of ZnO/GPET and ZnO/PET-ITO composite structures doped with different elements were analyzed,and the possible photocatalytic mechanisms of Ni-ZnO/GPET,Fe-ZnO/GPET and Cu-ZnO/GPET were investigated.The research contents and results are as follows1.B-ZnO nanorods doped with boron(B)were successfully prepared on PET-ITO and GPET substrates by hydrothermal method,respectively.Buffer layer can improve the orientation of B-ZnO growth.Compared with ZnO/PET-ITO,the B-ZnO composite structure grown on the GPET substrate is denser and has better c-axis preferred orientation.The photocatalytic performance test results show that the photodegradation efficiencies of B-ZnO/PET-ITO and B-ZnO/GPET are 69.56%and 81.15%,respectively,which confirmed that as a flexible growth substrate,PET with graphene buffer layer leads to the higher photocatalytic activity of B-ZnO.At the same time,the effect of B doping on B-ZnO/GPET was also discussed Compared with undoped sample,the photocatalytic reaction rate of B doped is 9.15%,which is higher than that of undoped-one2.Different metal-doped M-ZnO/GPET(M=Al,Fe,Ni,Mg,Cu)photocatalysts were synthesized on the GPET substrates by hydrothermal method.The effects of doped metals in ZnO were also studied on the crystal structure,morphology and photocatalytic performance The XRD analysis show M-ZnO/GPET with the hexagonal wurtzite structure.Meanwhile,from the FE-SEM images,we can see the incorporation of Al have the effected the morphology of ZnO to be a lamellar structure.The photocatalytic experiment results show that Cu-ZnO/GPET has significant light catalytic enhancement under UV light irradiation,compared with other M-ZnO,such as Ni-ZnO/GPET,Al-ZnO/GPET,Mg-ZnO/GPET,and Fe-ZnO/GPET photocatalysts.The degradation rate of methylene blue(MB)is 83.35%,meanwhile,the mechanism of enhancing the photocatalytic activity of Fe,Ni and Cu doped ZnO is also discussed3.Cu-ZnO/GPET nanorods with different-Cu doping concentrations(0%,3%,5%,7%,10%,and 15%)have been grown on GPET flexible substrates.The photocatalytic performance results show that the doping of Cu does not effectively effect on the crystal structure or micromorphology of ZnO.With the increase of Cu content,the photocatalytic degradation activity increases first and then decreases.The photocatalytic activity is the optimum when the Cu doping concentration is 10%.